I don't know if somebody changed something since 2022-05-03 (Comment #6 form @nrbrtx ), but my error message when starting firefox (snap) on Ubuntu Mate 22.04 in a guest session is different:
guest-qd9nle@ubrio22:~$ firefox
cannot create user data directory: /tmp/guest-qd9nle/snap/firefox/1860: Permission denied
I don't understand why there appears this Permission denied, as in /etc/apparmor.d/abstractions/lightdm the permission is: "owner /tmp/** rwlkmix,", so it seems to be ok. And more: the directory /tmp/guest-qd9nle/snap/firefox/1860 is created, despite the message.
I don't know if somebody changed something since 2022-05-03 (Comment #6 form @nrbrtx ), but my error message when starting firefox (snap) on Ubuntu Mate 22.04 in a guest session is different:
guest-qd9nle@ ubrio22: ~$ firefox qd9nle/ snap/firefox/ 1860: Permission denied
cannot create user data directory: /tmp/guest-
I don't understand why there appears this Permission denied, as in /etc/apparmor. d/abstractions/ lightdm the permission is: "owner /tmp/** rwlkmix,", so it seems to be ok. And more: the directory /tmp/guest- qd9nle/ snap/firefox/ 1860 is created, despite the message.